A method for run time zero byte compression of data on a communication bus of a vehicle includes determining a number of zero bytes provided in a data frame. The guide lever has a halfway hook engagement portion which, when the hook is in a halfway position between the releasing position and a restraining position and the striker is not in a position to be restrained by the hook, engages with the guide engagement portion to hold the hook in the halfway position. Removal of the ink pan and rolls facilitates cleaning of the rolls and the pan. The inlet shroud comprises an upstream end portion within which the fan inlet is formed and a downstream end portion which is removably connected to a separate portion of the fan housing.